Engine idling stop signal display apparatus

ABSTRACT

An idling stop signal display apparatus is connected to traffic relating equipment for prompting a running automobile to stop. The idling stop signal display apparatus comprises display means for prompting an automobile driver to stop an engine and to restart the stopped engine, and control means, including said display apparatus, which prompts engine stop by determining a preferable period of time based on an input signal from the traffic relating equipment and functions to prompt the stopped engine to restart by determining a preferable timing.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. application Ser. No.09/635,126, filed on Aug. 8, 2000, and currently pending before the U.S.Patent and Trademark Office.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to an automobile engine idling stop signaldisplay at an intersection or the like.

[0004] More specifically, this invention relates to an automobile engineidling stop signal display apparatus at an intersection or the like towait for a traffic signal lamp to change.

[0005] 2. Description of the Related Art

[0006] When automobiles wait for a traffic signal to change to red for apredetermined period of time, ordinarily, the drivers wait for thechange of the traffic signal while keeping engines in an idling state inmost cases. By continuing the engine idling, not only the fuel suppliedthereto during the idling time is wastefully consumed but also globalwarming substances such as carbon dioxide (CO₂) and the like and gasessuch as nitrogen oxide (NOx) and the like which are harmful to humanbodies are discharged. To cope with this problem, an “idling stopcampaign” is being conducted in some districts to promote the idlingstop of automobile engines when automobiles are at rest.

[0007] Apparatus for controlling the stop of automobile engines havebeen proposed. The engine stop control apparatus are arranged fortemporary stop of the automobile engines when the automobile stops at ared signal or meets a traffic jam. These apparatuses are proposed in thetechnologies disclosed in, for example, Japanese Unexamined PatentPublication No. 11-62650.

[0008] According to the technology disclosed in Japanese UnexaminedPatent Publication No. 11-62650, any one of a normal cruising mode or anidling stop/energy saving cruising mode is previously selected by a modeselection switch. In the case that the idling stop/energy savingcruising mode is selected, it is possible to stop an engine at temporarystoppage of an automobile and then to restart the engine, by theordinary driving operation such as the depression of a brake pedal andthe shift operation of a shift lever. By this operation, anidling-stop-controlled automobile can be realized, whereby fuelconsumption is saved and atmospheric pollution is prevented in a globalscale.

[0009] When a driver waits for signal change from red to green or adriver waits for train passing at a lowered gate of a railroad crossing,the driver usually keeps the engine in an idling state without stopping.The reason is to promptly start an automobile just after the red signalis changed to green or gate arm is lifted after train passing. However,gasoline is wastefully consumed by keeping the engine in the idlingstate during the automobile stoppage.

[0010] In addition to the above, the engine discharges global warmingsubstances such as carbon dioxide (CO₂) and the like and gases such asnitrogen oxide (NOx) and the like which are harmful to human bodies.Therefore, an “idling stop campaign” is being conducted in somedistricts to promote the idling stop when an automobile is at rest asdescribed above. However, a major reason why the “idling stop campaign”does not become widespread resides in the nuisance of stopping anengine.

[0011]FIG. 13 shows a discharge characteristic of an amount of nitrideoxide (NOx) before and after stopping an engine idling. In the FIG., “i”shows a NOx discharge level in idling state. Numeral ti denotes a timeat which idling is stopped and numeral t₂ denotes a time at which anengine is restarted. A slanting-lined region M₁ shows an amount ofexhaust gas that is reduced by an idling stop. A slanting-lined regionM₂ shows an excess amount of exhaust gas that is increased by highlyconcentrated exhaust gas at engine restart, in comparison with thecontinuous idling.

[0012] Thus, no NOx gas is discharged for a period of time t by stoppingthe idling, and the amount of exhaust gas reaches a peak value thatexceeds the level of the idling start by restart of the engine. It isthen lowered to the level of the idling state as a time passes. In thecase that the region M₂ is smaller than the region M₁, the idling stopis effective to reduce the exhaust gas. Note that curves showingvariations of the exhaust gases, which are similar to that of NOx, arealso drawn similarly as to CO₂, CO and THC.

[0013] However, there are cases in which it is not always preferable tostop idling when an automobile is stopped at a stop signal (red signal)and the like, for example, as shown below.

[0014] When an engine is restarted, the amount of fuel required in acranking process (a process for restarting the engine by rotating astarter motor) is more than the amount of fuel needed in continuousidling. In this case, fuel is much consumed by the idling stop.

[0015] When an engine is restarted, harmful exhaust gas are dischargedmore than that of the exhaust gases discharged in continuous idling. Inthis case, the harmful exhaust gas is discharged more than that in theidling stop.

[0016] A battery load is excessively increased when the headlamps areturned on at night or air conditioning is carried out. In this case,there may be a possibility that the battery goes dead and an enginecannot be restarted.

[0017] In the above cases, harmful effects are caused by the stop ofidling.

[0018] As a reason why “the idling stop” is not widely popularized eventhough a driver recognizes the effect of it, there is the conventionalcustom that the driver can not instantaneously recall the idling stopand misses a timing for the action, in addition to the driver'sbothersome feeling of the idling stop action.

[0019] Further, still another reason is that the driver may find itunpleasant to have to promptly run an automobile by restarting theengine idling just before signal changes from red to green or justbefore a crossing gate is lifted.

SUMMARY OF THE INVENTION

[0020] To solve the above problems, an object of the invention is toprovide an idling stop signal display apparatus as an apparatuseffective to make an “idling stop” campaign become widespread, theapparatus being arranged such that it prompts a driver to stop an engineat a proper timing while a traffic signal device displays a red signalor while the gate arm of a crossing gate is lowered and then notifiesthe driver of a time at which the engine is to be restarted.

[0021] In a particular embodiment of the invention, there is provided anidling stop signal display apparatus connected to traffic relatingequipment for prompting a walker or a traveling automobile to stop,comprising display means capable of making a display for prompting anautomobile at rest at least to stop an engine and to restart the stoppedengine; and control means having a function for determining a time zoneduring which it is preferable to stop the engine based on the signalinput from the traffic relating equipment and causing the display meansto make a display for prompting the engine to stop as well as a functionfor determining a time zone during which it is preferable to restart thestopped engine and causing the display means to make a display forprompting the engine to restart.

[0022] The traffic relating equipment may be a traffic signal deviceinstalled at an intersection or the like and connected thereto, and thecontrol means divides the time zone during which a red signal is turnedon for a predetermined period of time at predetermined intervals in atime series direction based on input red signal display information, andhas a function for causing the display means to make a display forprompting the engine to stop in the first divided section of a pluralityof divided sections and a function for causing the display means to makea display for prompting the engine to restart in the final section ofthe plurality of divided sections.

[0023] Specifically, in the case that the length of an preceding redsignal exceeds a predetermined period of time, the control means maycontrol the display means such that the display means sequentially makesa first display for prompting the engine to stop, a second display forprompting the engine to leave as it is which follows the first displayand a third display for prompting to restart the engine, which followsthe second display, whereas when the length of the information of theimmediately preceding red signal does not exceed the predeterminedperiod of time, the control means may control the display means suchthat the display means makes only the second display.

[0024] Further, the traffic relating equipment may be a crossing gate ofa railroad and connected thereto, and the control means may cause thedisplay means to make a display for prompting the engine to stop of theautomobile based on a signal input to the apparatus that indicates thata train has approached or a crossing arm has been lowered and to make adisplay for prompting the engine to restart based on an input signal tothe apparatus which indicates that the train has passed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a view showing the schematic arrangement of anautomobile engine idling stop system according to an embodiment of thepresent invention.

[0026]FIG. 2 is a view showing an example of the automobile engineidling stop system according to the embodiment of the present invention.

[0027]FIG. 3 is a view explaining an example of a signal transmitted bya transmitter.

[0028]FIG. 4 is a view showing a timing at which an automobile engine isrestarted after the idling thereof is stopped.

[0029]FIG. 5 is a graph explaining conditions under which an idling stopeffect can be obtained in the consumption of fuel.

[0030]FIG. 6 is a graph explaining conditions under which an idling stopeffect can be obtained in exhaust gases (NOx).

[0031]FIG. 7 is an example of flowchart showing the processing stepsperformed by the automobile engine idling stop system according to theembodiment of the present invention.

[0032]FIG. 8 is a view explaining the relationship between a trafficsignal device and an automobile at an intersection in the automobileengine idling stop system according to the embodiment of the presentinvention.

[0033]FIG. 9 is a schematic view showing timings at which the turning-onof the traffic signal lamps of the traffic signal device correspond toidling at the intersection and the like.

[0034]FIG. 10 is a block diagram showing the arrangements of a receiverand a transmitter.

[0035]FIG. 11 is a system diagram showing the functions of therespective sections of an embodiment of a signal display apparatus fordisplaying information relating to the idling stop of the automobileengine according to the present invention.

[0036]FIG. 12 is a view explaining an example showing how the signaldisplay apparatus of FIG. 11 is installed.

[0037]FIG. 13 is a graph showing the change of an amount of nitrideoxide (NOx) discharged before and after the idling of the automobileengine is stopped.

[0038]FIG. 14 is a view explaining the relationship between the contentsof display for prompting the stop of the engine and the contents ofdisplay of traffic signal lamps.

[0039]FIG. 15 is a view explaining a reference for determining whetheran idling display is necessary or not.

[0040]FIG. 16 is a front elevational view showing an example of adisplay surface corresponding to the display unit of FIG. 11.

[0041]FIG. 17 is a front elevational view showing an example of anotherdisplay surface corresponding to the display unit of FIG. 11.

[0042]FIG. 18 is a front elevational view showing an example of stillanother display surface corresponding to the display unit of FIG. 11.

[0043]FIG. 19 is a front elevational view showing another displayexample of the display unit of FIG. 18.

[0044]FIG. 20 is a system diagram explaining the functions of therespective units of a modification of the apparatus shown in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] First, an example of an embodiment of an apparatus and a systemof the present invention will be described below in detail withreference to the accompanying drawings. Note that the embodiment isarranged such that the idling of an automobile engine is stopped and theautomobile engine is restarted in response to a command transmitted froma traffic signal device.

[0046]FIG. 1 is a view showing the schematic arrangement of anautomobile engine idling stop system 10 according to the presentinvention. As shown in the figure, the automobile engine idling stopsystem 10 is arranged such that the command transmitted from atransmitter 14 disposed to a traffic signal device 12 (refer to FIG. 2)is received by a receiver 18 provided with an automobile 16 and thereceived command is supplied to a controller 20 which stops the idlingof an automobile engine and restarts the engine. In order to detect thestate of the automobile 16, the controller 20 is connected to a lightswitch 22, an air conditioner 24, a parking brake switch 26, a footbrake switch 30, an automobile speed sensor 28, a neutral positiondetecting switch 32 and an engine control unit 34, determines the stateof the automobile based on the signals supplied from the respectiveunits and controls the engine control unit 34, thereby stopping theidling of the automobile engine and restarting the engine.

[0047] The light switch 22 connected to the controller 20 turns on notshown head lamps and rear combination lamps as well as supplies a signalindicating that the head lamps and the rear combination lamps have beenturned on, that is, the switched state (ON/OFF state) thereof, to thecontroller 20.

[0048] The air conditioner 24 regulates room temperature of theautomobile 16 as well as supplies a signal indicating the operatingcondition (ON/OFF state) of the air conditioner 24 to the controller 20.

[0049] The parking brake switch 26 is mounted on a parking brake lever,detects the operating condition of the parking brake, and supplies thedetected signal to a meter panel so as to notify a driver of the presentcondition of the parking brake and supplies the signal to thecontroller.

[0050] The foot brake switch 30 is mounted on a foot brake 36 and turnedON when the foot brake 36 is actuated, turns on the rear combinationlamps to thereby notify how the foot brake is used to a followingautomobile, and supplies a signal indicating the operating condition ofthe foot brake to the controller 20.

[0051] The automobile speed sensor 28 is mounted on a transmission 38 ofthe drive system of the automobile 16 and detects an automobile speedfrom the rotational speed of the rotational shaft of the transmission38. Then, the automobile speed sensor 28 supplies the detectedautomobile speed to the meter panel (speed meter) as a signal so that atraveling speed is notified to the driver and supplies the detectedautomobile speed to the controller 20.

[0052] The neutral position detecting switch 32 is disposed in thevicinity of a shift lever for shifting the transmission 38, detects aneutral position and supplies a signal representing the result ofdetection to the controller 20.

[0053] The controller 20 detects the state of the automobile (travelingand stopping state, a load imposed on a battery 48, and the like) basedon the signals output from the light switch 22, the air conditioner 24,the parking brake switch 26, the foot brake switch 30, the automobilespeed sensor 28 and the neutral position detecting switch 32,respectively.

[0054] Further, a starter motor 40 for starting an engine 42, anignition switch 44 for starting the engine by rotating the starter motor40, an igniter for igniting the engine and a distributor 46 as well asthe controller 20 are connected to the engine control unit 34. Theengine control unit 34 starts and stops the engine 42 under the controlof the controller 20. Ordinarily, the driver starts and stops the engine42 by actuating the ignition switch 44.

[0055] Further, electric power to the electrical components mounted onthe automobile 16 is supplied from the battery 48 mounted on an engineroom. The power is supplied in such a manner that the negative terminalof the battery 48 is grounded to an automobile body and the positiveterminal thereof is connected to the respective electrical componentswhich are grounded to the automobile body.

[0056] Next, the signal transmitted from the transmitter 14 disposed tothe traffic signal device 12 will be described.

[0057] The traffic signal lamp driven by the traffic signal device 12 issequentially changed to red, green and yellow in an optional period oftime set respectively. Further, the period of time may be fixed or maybe changed externally according to the state of traffic jam or the like.

[0058] The transmitter 14 of the traffic signal device 12 transmits afrequency-modulated signal from the time when the traffic signal changesto red to the time when it changes to green. The signal frequency ismodulated such that a signal of the predetermined frequency is f₁ whenthe traffic signal lamp changes to red and then the signal frequency ismodulated to a higher frequency as a time passes so that it reaches apredetermined frequency f₂ at a time t_(A) when the traffic signalchanges to green as shown in FIG. 3. That is, the time-frequencycharacteristic of the output signal is represented by a straight line.Note that when the period of time for changing the traffic signal lampof the traffic signal device 12 is changed, the inclination of thestraight line of the time-frequency characteristic is changed so thatthe predetermined frequency f₂ is obtained at a time t_(A)′ when thetraffic signal lamp is changed to green. As a result, a signal, which ismodulated to satisfy the dot-dash-line shown in FIG. 3, is obtained.Further, in the above description, when the traffic signal lamp of thetraffic signal device 12 is changed to red, the frequency of the signalis modulated to a higher frequency as a time passes. However, thefrequency thereof may be modulated to a lower frequency as a timepasses.

[0059] Next, it will be described how the controller 20 stops the idlingof the automobile engine and the restarts it based on the signaltransmitted from the transmitter 14.

[0060] In general, automobile engines have different enginecharacteristics (characteristics of fuel consumption, exhaust gases orthe like) depending upon the types and specifications of the engines.That is, a period of time (idling stop effective period of time), whichis required to obtain the idling stop effect (reduction in wasteful fuelconsumption and harmful exhaust gases), is not constant depending uponthe respective engines. Therefore, the controller 20 determines whetheridling is to be stopped or not depending upon the idling stop effectiveperiod of time of each engine, and controls the idling stop and theengine restart.

[0061] When the period of time t_(s) until restart of the enginesatisfies the condition to be described below, the controller 20 judgesthe idling stop effective and stops idling of the automobile engine.

[0062] When the engine is restarted, an amount of fuel consumption isincreased by M_(R)(g) as shown in FIG. 5. In contrast, an amount of fuelwhich can be saved by stopping idling during the period of time t_(s)can be represented by m_(f x) t_(s)(g), where an amount of fuel consumedin continuous idling during t_(s) is represented by m_(f) (g/s).Accordingly, the idling stop effect can be obtained when the conditionm_(f x) t_(S)>M_(R) is satisfied, i.e., the condition t_(s)>M_(R)/m_(f)is satisfied.

[0063] Further, when the engine 42 is restarted, an amount of nitrideoxide (NOx) discharged from the engine 42 is also increased by M_(NOx)(g) as shown in FIG. 6. An amount of discharged NOx which can be reducedby stop idling during the period of time t_(s) is represented bym_(NOx x) t_(s), where an amount of NOx discharged in continuous idlingduring t_(s) is represented by m_(NOx) (g/s). Accordingly, the idlingstop effect can be obtained when the condition m_(NOx) t_(S)>M_(NOx) issatisfied, that is, the condition t_(S)>M_(NOx)/m_(NOx) is satisfied.

[0064] Further, the hydrocarbons (HC) discharged from the engine 42 isalso increased by the restart of the engine 42 likewise the NOx, and theidling stop effect can be obtained when the conditiont_(s)>M_(HC)/m_(Hc) is obtained, where an amount of HC discharged isrepresented by m_(HC) (g/s) and an amount HC increased when the engine42 is restarted is represented by M_(HC) (g).

[0065] Next, an algorithm for calculating the period of time t_(s) willbe described with reference to FIG. 3, the period of time t_(s) beingfrom the time at which the automobile 16 reaches a particular regionsuch as an intersection or the like and stops there to the time at whichthe engine 42 is to be restarted as shown in FIG. 4. The period of timet_(s) is important as a base of the criteria time T for judgment.

[0066] The controller 20 obtains the signal transmitted from thetransmitter 14 of the traffic signal device 12 through the receiver 18,and calculates the period of time until the traffic signal of thetraffic signal device 12 changes to green as described later.

[0067] When the time at which the signal transmitted from thetransmitter 14 is represented by a time t_(x), and the frequency of thesignal at the time is represented by f_(x) and an amount of change ofthe frequency after a period of time Δt passes from the time t_(x) isrepresented by Δf, the inclination of the straight line of thetime-frequency characteristic of the signal transmitted from thetransmitter 14 is made to Δf/Δt. Therefore, the straight line can berepresented by the following formula.

f=Δf/Δt _(x) t+f ₁  (1)

[0068] f₁ is represented by the time t_(X) at which the signaltransmitted from the transmitter 14 is received and a frequency f_(X) atthe time, therefore, the formula (1) can be represented by the followingformula.

f=Δf/Δt _(x) t+f _(x) −Δf/Δt _(x) t _(x)  (2)

[0069] The period of time t_(S) until the traffic signal changes togreen is a value obtained by subtracting the time t_(X) at which thesignal is received and a time Δt+α(α: coefficient of calculation time)necessary to the calculation from the time t_(A) at which the trafficsignal lamp is changed to green.

t _(s=t) _(A)−(t _(X) +Δt+α)  (3)

[0070] When t_(A) is represented by the time t_(x) at which the signaltransmitted from the transmitter 14 is received and the frequency f_(x)at the time, the formula (3) can be represented by the followingformula.

t _(s)=(f ₂ −f _(x))_(x) Δt/Δf _(A)−(Δt+α)  (4)

[0071] Note that the time Δt+α necessary to the calculation can beignored because it is a minute period of time.

[0072] Therefore, if the frequency f₂ of the modulated signal at whichthe traffic signal changes to green is settled in advance, the period oftime t_(S) until the traffic signal change can be calculated fromrelation between the frequency f_(X) of the received signal and thefrequency deviation Δf during the time deviation Δt of the receivedsignal.

[0073] And, by determining in advance the frequency f₂ at which thetraffic signal changes to green, the time period of time t_(S) until thetraffic signal is changed can be calculated even if the period of timeuntil the traffic signal changes to green is variable (the time t_(A) atwhich the traffic signal is changed to green is not constant). Note thatf₁ may be or may not be predetermined.

[0074] After the period of time t_(S) until the traffic signal lamp ischanged is calculated, the controller 20 judges whether the idling is tobe stopped or not based on the above condition. Note that the time t_(S)is not the time when the traffic signal changes actually to green asshown in FIG. 4. It is preferable that the engine is restarted prior tothe change of the traffic signal by providing the psychological idlingpreceding period of time. The psychological idling preceding period oftime permits the engine 42 to be smoothly restarted without giving anyanxiety to the driver.

[0075] Subsequently, the operation of the embodiment will be describedbelow with reference to the flowchart of FIG. 7.

[0076] First, it is judged whether the automobile 16 is in the statethat the idling of the engine 42 can be stopped or not. In theembodiment, the controller 20 judges whether the lamps are turned on ornot based on the signal supplied from the light switch 22 at step 100.When the judgment is YES, that is, the automobile is not in the statethat the idling can be stopped, the idling is continued and the processis finished. Whereas, when the judgment is NO, the controller 20determines whether the air conditioner 24 is used or not based on thesignal supplied from the air conditioner 24 at subsequent step 102. Whenthe determination is YES, that is, the automobile is not in the state toenable to stop the engine idling likewise the step 100, the idling iscontinued and the process is finished. Whereas, when the determinationis NO, the process goes to subsequent step 104.

[0077] At step 104, it is determined whether the receiver 18 hasreceived the modulated signal transmitted from the traffic signal device12 as described above or not. When the determination is NO, step 104 isrepeated until the signal transmitted from the traffic signal device 12is received.

[0078] And, when the judgment at step 104 is YES, the process goes tosubsequent step 106, and the period of time t_(S) is calculated asdescribed above based on the signal received from the traffic signaldevice 12.

[0079] At step 108, it is judged whether the automobile 16 is at rest ornot. The judgment is carried out by checking whether the signal outputfrom the automobile speed sensor 28 indicates 0 Km/h, whether the footbrake switch 30 is turned ON, whether the parking brake switch 26 isturned ON, and whether the neutral position detecting switch 32 isturned ON (at the neutral position). In the case that all the abovejudgments are affirmed, automobile is judged as at rest. Note that thejudgment at step 108 is not limited to the above method, for example,any sole one or plural combination of the above checking items, i.e.,the automobile speed sensor 28, the foot brake switch 30, the parkingbrake switch 26, and the neutral detecting switch may be used to judge aresting state of the automobile.

[0080] In the case that any one of the above items at step 108 isdenied, steps 100 to 108 are repeated until the automobile is detectedas in a rest state. In the case that the judgment at step 108 isaffirmed YES, the process goes to subsequent step 110 and the period oftime T (idling stop time) is calculated by subtracting the period oftime until the automobile stops actually after receiving the signal andthe psychological idling preceding time of period from t_(S) which iscalculated at step 106.

[0081] At step 112, the controller 20 determines whether the idling stopperiod of time T is effective or not from a viewpoint of fuelconsumption. If the judgment is NO, that is, it is judged that fuel ismuch consumed by stop/restart of the engine, the idling is continued andthe process is finished. On the contrary, if the judgment is YES, theprocess goes to subsequent step 114.

[0082] At step 114, the controller 20 judges whether the idling stopperiod of time T is effective or not from a viewpoint of an amount ofexhausted NOx. If the judgment is NO, it is judged that NOx is muchdischarged by stop/restart of the engine. The idling is continued, andthe process is finished. On the contrary, if the judgment is YES, theprocess goes to subsequent step 116.

[0083] At step 116, the controller 20 judges whether the idling stopperiod of time T is effective or not from a viewpoint of exhausted HCwhich is increased when the idling is stopped and the engine isrestarted. If the judgment is NO, that is, it is judged that HC is muchexhausted by stop/restart of the engine being restarted, then idling iscontinued to steps 112 and 114, and the process is finished. On thecontrary, if the judgment is YES, the process goes to subsequent step118.

[0084] At step 118, the controller 20 controls ignition by the enginedistributor 46 through the engine control unit 34, and stops the engine.

[0085] At step 120, the controller 20 judges whether the idling stopperiod of time T has passed or not after the idling is stopped. If thejudgment is NO, the process goes to step 124 and it is judged whetherthe engine is to be restarted or not. Note that the judgment at step 124is carried out based on whether the driver has actuated the ignitionswitch 44 (operation for starting the starter motor 40) or not. If thejudgment at step 124 is NO, steps 120 and 124 are repeated until thedetermination at step 120 or 124 becomes YES.

[0086] If the judgment at step 124 is YES, it is judged that the enginehas been restarted by the intention of the driver and the process goesto step 126 at which the starter motor 40 is started by the ignitionswitch 44 and the engine 42 is restarted, whereby a series of theprocessing steps are finished.

[0087] If the judgment at step 120 is YES, the process goes to step 122at which the controller 20 rotates the starter motor 40 through theengine control unit 34 so as to restart the engine, whereby the seriesof the processing steps are finished.

[0088] Thus, the period of time t_(S) until the traffic signal changesto green is calculated based on the signal from the traffic signaldevice 12 (steps 104 and 106) and it is judged whether the idling is tobe stopped or not based on the calculated period of time t_(S) until thetraffic signal changes to green and the period of time until the idlingstop effect is obtained (steps 110-118). Accordingly, the wastefulconsumption of fuel and the discharge of harmful exhaust gases can bereduced by stopping the idling and restarting the engine 42 without anydetrimental effects caused by the idling stop.

[0089] Further, since the engine is restarted before the idling stopperiod of time T passes, that is, before the traffic signal is changedto green (preceding by the idling preceding period of time), the enginecan be restarted without giving any anxiety to the driver.

[0090] While the idling is stopped based on the signal transmitted fromthe traffic signal device 12 in the above embodiment, the presentinvention is not limited thereto. For example, the transmitter 14 of theembodiment may be mounted on a beacon for detecting traffic jam, or thelike. This arrangement is effective when the automobile is compelled towait for the traffic signal to change at a place apart therefrom due toa large traffic jam. And, when the automobile 16 is stopped not due tothe traffic signal change to red but due to a traffic jam, a stop periodof time of the automobile is calculated. And, by judging whether thecalculated stop period of time is effective or not for the idling stop,the wasteful consumption of fuel and the discharge of harmful exhaustgases can be reduced without giving any anxiety to the driver.

[0091] In the above embodiment, when the lamps are turned on or when theair conditioner is used, it is judged that the automobile is not in thestate to enable to stop idling, and the idling is continued. However, itmay be possible to stop the idling after the present state of theautomobile is stored and the lamps and the air conditioner are turnedOFF and then to restore them to the original states when the engine 42is restarted.

[0092] In the above embodiment, the control method of the idling stop(and restart) during the traffic signal changes from red to green hasbeen explained. In the case that an arrow signal to indicate a gostraight or turn left/right is used, the wasteful consumption of fueland discharge of the harmful exhaust gas can be reduced without anyanxiety of the driver, by using another frequency signal in the otherfrequency band and by detecting the state of the direction indicator, assimilarly to the embodiment.

[0093] The hardware of an apparatus according to the present inventionand the timing chart thereof will be described with reference to FIGS. 8to 10 as another embodiment which substitutes for the embodimentdescribed with reference to FIGS. 1 to 7.

[0094]FIG. 8 shows an example view to explain the relationship between atraffic signal indicator and an automobile 16 at an intersectionaccording to the embodiment of the present invention for stopping theidling of an automobile engine at the intersection. The traffic signalindicator 12, idling stop (IS) signal lamp unit (signal display) 12′ anda control signal transmitter 14 are installed at the intersection.

[0095] The signal from the control signal transmitter 14 is transmittedto the receiver 18 of the automobile 16 which is shown in FIG. 10, byusing infrared rays. The traffic signal indicator 12, the idling stoplamp unit 12′ and the control signal transmitter 14 are connected to atraffic signal controller 50.

[0096]FIG. 9 is a schematic view to show the relation between thetraffic signal indication and idling. FIG. 9 shows a sequential cycle ofsignal colors, green (G), yellow (Y), red (R), and green (G) along atime axis. The period of time of red (R) is further divided into periodsof time of A, B and C in the upper view, and times t₉, t₈. . . ti areshown in the lower view in relation to the turned-on period of time ofthe red (R). The period of time A shows a preferable time region of stopidling of the automobile which stops movement at a particular area suchas the intersection. During the period of time B (t₄−t₁ in the examplecase of FIG. 9) the automobile keeps idling without interruption eventhough it stops movement, that is, the automobile 16 keeps an idlingstate as it is during the period of time B. Note that since the aboveperiods of time vary depending upon the characteristics, type and thelike of an automobile engine, these are set up to optimum values of theengine at the automobile side (on board apparatus of the automobile).FIG. 9 shows an example of an automobile which is set up B (t₄−t₁) as anoptimum period of time of the engine. The period of time C is apsychological idling preceding period of time, and at time prior togreen signal indication, the engine starts idling.

[0097]FIG. 10 is a block diagram showing the system configuration of atransmitter device 14 installed at a pedestrian crossing, anintersection or the like and a receiver device 18 mounted on anautomobile. The transmitter device 14 as a signal transmitting sectionfor transmitting a signal for stopping idling includes a timinggeneration unit 14A, an IS (idling stop) signal generation unit 14B andan IS signal modulation and transmission unit 14C.

[0098] The traffic signal controller 50 installed at the intersection orthe like turns on the traffic signal lamps of the idling stop lamp unit12′ and generates a timing signal including t₁, t₂, to t₉. An IS signaldisplay and drive unit 14D drives the idling stop lamp unit 12′ byreceiving the timing signal. The signal for indicating the idling stopof the engine is modulated by the IS signal modulation and transmissionunit 14C and transmitted as an infrared signal or a radio wirelesssignal.

[0099] The receiver device 18 mounted on the automobile includes areceiver unit 18A, an IS signal encoding unit 18B, an IS timing unit18C, a condition determination unit 18D and an idling stop controller18E. An automobile state discrimination unit 20 discriminates variouskinds of information as to the automobile and the like and sends thesignal to the condition determination unit 18D. The engine mounted onthe automobile 16 is controlled by the signal from the idling stopcontroller 18E.

[0100] Next, an embodiment of a signal display apparatus of thisinvention that gives the idling stop information to the driver will beexplained hereunder in detail with reference to the drawings.

[0101]FIG. 11 shows a block diagram explaining the functions of therespective components of the idling stop signal display apparatus.

[0102]FIG. 12 shows an example in which the apparatus of FIG. 11 isadditionally mounted on a traffic signal device installed at anintersection.

[0103] In FIGS. 11 and 12, numeral 101 denotes the traffic signal of thetraffic signal device and numeral 102 denotes a traffic signalcontroller for controlling the operation of the traffic signal 101.Numeral 115 denotes a display unit (hereinafter, called the signaldisplay unit) for displaying indication whether the engine idling shouldbe stopped or should be kept as it is when the automobile stops by thered signal at the intersection, and for displaying indication to informrestart timing of the engine to the automobile in idling stoppage.Numeral 110 denotes a controller (hereinafter, called an idling signalcontroller) for controlling the operation of the signal display unit115.

[0104] The idling signal controller 110 is composed of a power supplyunit 111, an interface circuit 112, a display controller 113 and adisplay drive unit 114. The power supply unit 111 and the interfacecircuit 112 are connected to the traffic signal controller 102 through acable 109. The power supply unit 111 supplies electric power to thedisplay controller 113 and the display drive unit 114 and supplies theelectric power to the signal display unit 115 through the display driveunit 114 too.

[0105] The display controller 113 receives red signal information fromthe traffic signal controller 102 through the interface circuit 112,controls the display drive unit 114 based on the information and changesthe indication displayed on the signal display unit 115.

[0106]FIG. 14 shows relation between display to prompt the driver tostop idling and a traffic signal display.

[0107] In FIG. 14, G, Y and R in the display L₁ show time zones ofgreen, yellow and red signal respectively.

[0108] A, B and C of an idling signal display L₂ show time zones ofindication of “stop engine”, “leave engine as it is” and “restartengine” respectively.

[0109] In FIG. 15, S shows a reference period of time in which the areaM₁ is equal to the area M₂ in FIG. 13. Therefore, the period of time forindicating “stop engine” is equal to (R-S).

[0110] P is the psychological idling preceding period of time by whichthe driver can keeps his mind calm at starting the automobile.Therefore, the period of time to indicate “leave engine as it is”, isset up to (S-P) which is obtained by subtracting the preset idlingpreceding period of time from the reference period of time S.

[0111] The display controller 113 judges whether the idling stop signalis to be displayed or not based on the input information of thepreceding red signal and displays indication of “stop engine”, “leaveengine as it is” or “start engine” sequentially during the red signalbased on the judgment.

[0112]FIG. 15 shows the traffic signal sequences to explain judgmentcriteria whether idling display operates or not. In case of L₁₁, sincethe period of time of a red signal R₁ is longer than the referenceperiod of time S, the idling signal is displayed. And in case of L₁₂,since the period of time of a red signal R₂ is shorter than thereference period of time S, the idling signal may display “leave engineas it is” continuously during the period of the red signal or any idlingdisplay may not be performed.

[0113]FIG. 16 is an example of a front view showing the display of asignal display unit 116 that corresponds to the signal display unit 115of FIG. 11 and FIG. 12. The signal display unit 116 displayssequentially “stop engine” 116 a, “leave engine as it is” 116 b and“restart engine” 116 c. In this example, however, the term “engine”which is commonly used in the above three indications, is alwaysdisplayed on the display and the terms “stop”, “leave as it is” and“restart” are selectively illuminated at each time required.

[0114]FIG. 17 is a second example of front view showing the display of asignal display unit 117 that corresponds to the signal display unit 115of FIG. 11 and FIG. 12. In this example, a plurality of windows 117 a,117 b, 117 c and 117 d are formed on a display surface and thecharacters of “stop engine”, “leave engine as it is” and “start engine”are repeatedly displayed in the windows by being scrolled one characterby one character from right to left.

[0115]FIG. 18 is a third example of front view showing the display of asignal display unit 118 that corresponds to the signal display unit 15of FIG. 11 and FIG. 12. In this example, “stop engine”, “leave engine asit is” and “restart engine” are sequentially displayed by two groups oflamps, which are composed of red LEDs and green LEDs.

[0116] For example, numeral 118 a in FIG. 18 shows “stop engine” by theemission of the red light, numeral 118 b shows “leave engine as it is”by violet color obtained by mixing the red light and green light, andnumeral 118 c shows “restart engine” by the green light.

[0117] In addition to the above, various kinds of the display methodsare available. FIG. 19, for example, shows another display example ofthe display unit 118 of FIG. 18, wherein numeral 119 a shows “stopengine”, numeral 119 b shows “leave engine as it is” and numeral 119 cshows “restart engine”.

[0118]FIG. 20 shows an example of a modified block diagram of the idlingstop signal display apparatus shown in FIG. 11 and FIG. 12. Theapparatus shown in FIG. 20 is used by connecting to a crossing gatecontroller installed at a railroad crossing and composed of an idlingsignal controller 120 and a signal display unit 125. The idling signalcontroller 120 is a controller for controlling operation of the signaldisplay unit 125.

[0119] The idling signal controller 120 is composed of a power supplyunit 121, an interface circuit 122, a display controller 123 and adisplay drive unit 124. The power supply unit 121 and the interfacecircuit 122 are connected to a railroad crossing gate control circuitbox 103 by a cable 129.

[0120] The power supply unit 121 receives the electric power from thepower supply unit 133 of the railroad crossing gate control circuit box103 and supplies it to the display controller 123 and the display driveunit 124 and also supplies it to the signal display unit 125 through thedisplay drive unit 124.

[0121] The interface circuit 122 receives information about the state ofa railroad crossing gate arm and a train passing signal from theinterface circuit 132 of the crossing gate control circuit box 103.Information about the state of the railroad crossing gate arm from agate arm drive mechanism 130 and a train passing signal from a crossinggate control circuit 131 are sent to the display controller 123 throughthe interface circuits 122 and 132. The display controller 123 controlsthe display drive unit 124 based on the above input information andsignal and changes the display contents of the signal display unit 125.That is, when the display controller 123 receives a gate arm loweringcompletion signal as the gate arm state information, it causes thesignal display unit 125 to make a display for prompting “stop engine”,and when the display controller 123 receives the train passing signal,the signal display unit 125 display “restart engine”.

[0122] In the above case, the train is given priority of passing thelength of the period of the railway crossroad and also the time lengthof being blocked by the gate arm cannot be presumed. Accordingly, theindications on the signal display unit 125 are limited to “stop engine”or “restart engine”. Indication of “leave engine as it is” is notdisplayed. The specific structure of the display may be arrangedsimilarly to those of FIG. 16-FIG. 19.

[0123] The structure and the form of the signal display unit of theidling stop signal display apparatus connected to the traffic signaldevice or to the crossing gate are able to be variously realized inaddition to those shown in FIG. 16-FIG. 19. However, any of them isincluded in the scope of this invention as long as it satisfies the gistof this invention.

[0124] As described above, this invention is to prompt engine stop tothe automobile in stoppage and to give information of engine restarttiming to the automobile in stoppage.

[0125] And also this invention rouses the driver's effort to contributethe environment protection, and is useful to reduce the exhaust gas.

What is claimed is:
 1. An idling stop signal display apparatus connectedto a traffic relating equipment for prompting a running automobile tostop, comprising: display means for prompting an automobile driver tostop an engine and to restart the stopped engine; and control means,including said display apparatus, which prompts engine stop bydetermining a preferable period of time based on an input signal fromthe traffic relating equipment, and which functions to prompt thestopped engine to be restarted by determining a preferable timing,wherein the timing of the prompts is based on a car's amount of harmfulexhaust gases reduced by idling stop exceeding an amount of harmfulexhaust gases which are excessively discharged, beyond a normal idlingamount, by engine restart.
 2. An idling stop signal display apparatusaccording to claim 1, wherein: said traffic relating equipment is atraffic signal device; and said control means divides the red signaltime zone into three (3) predetermined periods of time, and has afunction for causing said display means to make a display for promptingto stop the engine at the first divided period of time and to restartthe engine at the third (last) divided period of time.
 3. An idling stopsignal display apparatus according to claim 2, wherein said trafficsignal device is installed at an intersection.
 4. An idling stop signaldisplay apparatus according to claim 2, wherein said traffic signaldevice is installed at a railroad crossing.
 5. An idling stop signaldisplay apparatus according to claim 1, wherein in the case that a redsignal time period exceeds a predetermined period of time, said controlmeans displays a first indication, which prompts to “stop engine,” asecond indication, which prompts to “leave engine as it is,” and a thirdindication, which prompts to “restart engine,” in that order, while inthe case that the red signal time period does not exceed thepredetermined period of time, only the second indication is displayed.6. An idling stop signal display apparatus according to claim 1, furthercomprising: an idling stop signal transmitter that transmits a firstsignal to prompt “idling stop,” a second signal to prompt “leave engineas it is,” and a third signal to prompt “engine restart,” in that order,during a red traffic signal time period.
 7. An idling stop signaldisplay apparatus according to claim 6, wherein said idling stop signaltransmitter is installed at roadside.
 8. An idling stop signal displayapparatus according to claim 1, wherein said traffic relating equipmentcomprises a crossing gate of a railroad and wherein said control meanscauses said display means to make a display for prompting to stop theengine of an automobile based on an input signal to the apparatusindicating that a train is approaching or a crossing arm has beenlowered and to restart the engine based on an input signal indicatingthat the train has passed or that the crossing arm has been raised.